RFR: JDK-8162504: [SA testbug] TestInstanceKlassSize.java and TestInstanceKlassSizeForInterface.java fail on Mac OS

[Jini George]

Requesting reviews for the following SA testbug:

https://bugs.openjdk.java.net/browse/JDK-8162504
Webrev: http://cr.openjdk.java.net/~jgeorge/8162504/webrev.00/

Thank you,
Jini.